Process of purifying hydrocarbons



Oct. 7, 1930. w. H. ow

PROCESS OF PURIFYING HYDROCARBONS Filed Sept. 6, 1927 N u N INVENTOR l//L 50N /7.' L 0W BY 4mm/Ku. ATTORNEY Patented Oct. 7, 1930 UNITED STATES PATE-NT OFFICE WILSON H. LOW, F LONG BEACH, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGNMENTS. TO RICHFIELD-` OIL COMPANY OF CALIFORNIA, OF LOS ANGELES, CALIFORNIA, A

CORPORATION OF IDELAARIJ .PROCESS 0F PURIFYING AHYDIROGARBONS Animation med septennier e, 1927. serial no. 217,804.-v

, distillation, rendering the stock sour to the` doctor test. A A y Theobject of' this invention is to produce ing a jgasoline or naphtha stock which contains mercaptans or other sulphur bearing hydrocarbons common-l called sourgaso line or naphtha stock with dry lead sulphide, I *20. particularly in al fine state of division to render the treated gasoline sweet to the doctor test by a sequence 'of operations in which the lead sulphid'emaybe kept in an active state by intermittent revivification opera.'- tions.

lead .sulphide from a Water solution of a lead salt, using hydri'vgen sulphide ora Watersoluble sulphide` washing the precipitate to removesoluble impurities and dnying ata teniper'ature. of approximately 110 C.. ["he gasoline stock sweetened by my invention 1s more stable in color vthan bythe process where "black-strap alone isused. "I liave also discovered Athat the lead sulphide may be kept in an active state 'by intermittent treatments with a water solutionof sodium sulphide.

The gasoline stock to be treated is preferably I one which has hadapreliminary caustic Soda treatment or other` treatment which will remove hydrogen sulphide, and may be one astable and sweet gasoline stock by treat-` I am aware that it 'is common knowledge Y which has had a preliminary treatn'ient with sulphuric acid and caustic soda. Mereapt-ans y l are among those'substances which cause a .gasoline stock to show a positive doctor test andit is to the treatment of this class'of compounds that this inventionv is particularly adapted, although it is to be understood .that this invention is not limited thereto.

n My process in general consists in bringing dry gasoline into Contact with pure dry lead sulphide by filtration or percolation through a material containing lead sulphide. The

- time of contact dependssomewhat on the amount of lead sulphide contained hy the filter medium'A and its ineness. The filter medium employed may be any dry inert car- -rier suchas asbestos fiber, diatomaeeous earth, fullers earth and the like.

' In lthe sweetening process as Carried out by my invention, the lead sulphide appears to act in aeatalytic manner, changing the mercaptans into dialkyl dlsulphldes. I have determined that-asmall amount of lead sulphide 'will sweeten a large amount ofsour gasoline and that-the lead sulphide may be used for a relatively longr period of timewithout re\-'ivitieation, and that the revivification may be accomplished by intermittent treatments of the spent sulphide with a water solution of sodium sulphide.-

I The lead sulphide employedma'y. be preparedl by passing hydrogen sulphide into a water solution of any of the Well-known lead salts such as lead acetate, lead chloride, and the like.

lith the foregoing preliminary explanation. the lvieterred formof our invention will noujhe niort-.fully explained hyrefereuce to the. accompany-'ingdrawing. which is -a diagranunatial represent-ation of an apparatus in which t-he invention may be performed.

In the drawing, l represents generally a tank forholding the sour gasoline to be. treated. A Apipe 9. controlled by the valve 3 connects thegasoline stock tank toJ a pump 4. The pipe 5 controlled by the valve 6 connects the pump 4 to the filter 7. Connected at the top/ot tilt-er 7 is a man hole 8 through which the filter vmediumof lead sulphide and diatomaceous earth may be charged Into the filter. The figure 11 ,represents the charge .of lead sulphide and diatoniaceous earth interposed on the grate 9. repre- -sents a filter cloth coveringthe grate 9. A pipe 12,'con'troller by thev valve 13, is connected to the filter 7 near the top. A pipe 29 A controlled bythe valve 30 connects the filter l yand leads to a source of waste steam notA the `apparatus described is as follows: A

7 to the discharge side of a pump 28. A4 pipe 24 controlled by a. valve 25 connects the tank 23 to the suction side of pump 28. A pipe 26 controlled byV a valve27 is connected to the pipe 24, an leads to a source of water supply notshown. Pipe 21, controlled by the valve 22 connects tank 23 at thetop tothe pipe .14.

A pipe 14, controlled by valves 15 and 15V is connected to the filter- 7 at the bottom. A

'branch pipe 19, controlled by a valve 20 connects the pipe 14 to the sour7 gasoline tank 1. A pipe 16, controlled by the valve 17, con.

shown.

The preferred process as carried out with filter 7 is charged to the required height with a mixture of lead sulphidean'd diatomaceous earth and the gasoline or naphtha stock `to be treated4 contained in the gasoline stock tank 1 is discharged by the pump 4. into the 'filter 7 passing through lt-he pipes 2and 5 `controlledby the valves 3v and 6. Asv soon as the filter 7 has been charged with a sufficient amountl of the gasoline stock to be treated, the valves 3 and 6 are closed andthe operation of the pump 4 discontinued. The valves 15 and 17 are now open, keeping the valves. 15, 22 and 2O closed, which permits the gasoline coming through the'filter-to flow into the sweetened gasoline storage tank 18.

The pump 4 is intermittently operated dis-` charging the gasoline to be. treated into the filter 7 as described, so as to keep a sufficient column of gasoline above the filter bed 11. As soon as the gasoline passing,r into the sweetened gasoline storage tank 18 commences to its gasoline stock. The lead sulphide is now -show a positive test to the doctor solution, valve 17 is closed and valve '20 is open by means ofwhich the filter 7 is drained of revivified by treating the same Apreferably with a water solution of sodium sulphide,

followed by a water wash and then drying the filter mass withheated dry air. This is accomplished by operating the pump 28 and opening. the valvese25 and 30. .the valves 17,

20 and 15 being closed. As soon as a sufficient quantity of the water solution of sodium sulphide has been introduced into the vfilter 7 theoperation of pump 28 is discontinuedy and the valve 25 closed andthe valves 15 and 22 are opened, permitting the Water solution of sodium sulphide after passing through the filter bed to pass back into the tank 23. As soon as a sufficient amount ofthe water solution of sodium sulphide has passed through the filter bed 11 to revivify the lead sulphide, the filter mass is washed with water which is accomplished by again operating the pump 28 opening the valves 27 and 30 which permits a flow of Water to pass into the filter 7. The valve 22 is now closed and valves 15 and 15 are opened, permitting the water passing through the filter to run to waste. As soon as. the water passing through the filter bed 11 shows no appreciable amount of sodium sulphide, the introduction of. water into the filter 7 is discontinued and the valves-30 and 27 closed. As soon'as the filter 7 has beeir drained of its Water content,the valves 15 and 15 are closed and the valves 13 and V35 are opened. The filter mass is now dried, which is accomplished by blowing f air through the filterbed in which operation the air from blower 31 passes through the steam heater 33 entering the filter 7 below the grate 9. The heated air passes upward through the bed 11 and out through the pipe 12. As soon as the filter bed 11 is substantially dry the operation of the air blower 31 is discontinued, the valves 35 and 13 are closed, and" the filter 7 is again charged with the sour gasoline stock to be sweetened As a specific example, in the treatment of ,gasoline stocksderived from cracking California petroleum oils, it was found that the amount of lead sulphide necessary to re.- move all sourness to the doctor test ranged from 1/10 to f5 pounds per barrel of gaso-l line stock treated, before it was found necessary to revivify the lead sulphide.

By the term sourfwe mean a petroleum oil containing mercaptans, or other hydrocarbons which produce a positive test to a `standard doctor solution. and by the term sweet we mean a petroleum oil substanlially free from the above named constituents.4

By the term doctor test we means that well-known .test employed byehemists to dep' termine a sour or sweet petroleum oil stock, the-term negative-7 to the doctor test *meaning that the oil stock is sweetf and positive to the doctor test meaning that the oil is soun It is also to be understood that any gasoline stock or petroleum oil distillate may be treated by our invention and rendered sweet, and that any petroleum oil distillate may ormay not have vhad prior treatments known in the art, such as treatments with acid and'ca'ustic soda, before being sweetened by my invention. l f' In the preferred embodiment of' this inven- 'tion, have described an operation in. which heated air is employed after the revivifying operation to dry the lead sulphide. It is to be understood, however, that superheated steam or other hot inert gases may be elnploved for this purpose.

ll'hile the process herein described is Well adapted for carrying out the object of the present invention. it is to be understood that various modifications and changes may be made without departingvfroln the spirit of the invention and the invention includes all such changes and modifications as come Within the scope of the appended claims.

lVhat I claim is:

1.l A process of treating gasoline stock, comprising ltering the same through a filter bed containing dry coniminuted lead sulphide and dried by contact with air, prepared by reacting on a. water solution of a lead salt with a vater soluble sulphide. and intermittently revivifying the lead sulphide by treating the same with a Water solution of a soluble alkali sulphide.

2. A process of treating gasoline stock derived from cracking petroleum oils to render the same sweet"` to the doctor test, comprising filtering the same throu h comminuted dry lead sulphide and drie by contact with air. prepared by reacting on a water solution of a lead salt with a water soluble sulphide, and intermittently revivifying the filter mass by treating the same with a. water solution of a soluble sulphide.y

3. A process of treating gasoline which is sour to the doctor test to render the same sweet to the doctor test comprising contacting the same through a filter bed containing comxninuted dry lead sulphide and dried by contact with air, prepared by react ing on a water solution of a lead salt with a. water soluble sulphide, for a period of time s'uicient to render the gasoline sweet and intermittently revivifying the lead sulphide by treating the same with a Water solution of an alkali sulphide.

4. A process of treating gasoline stock which contains mercaptans to render the same sweet" to the doctor test comprising liltering the same through al mass containing comminuted dry lead sulphide and dried by contact with air. prepared by reacting on a Water solution of a lead salt with a water soluble sulphide. to render the same sweet" to sweet to the docttir test and intermittently revivifying the lead sulphide by treating the same with a water'solution of an alkali sulphide.

In testimony whereof I atlx m WILSON LOW.

i ature. 

